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Int Poster J Dent Oral Med 13 (2011), No. 3     15. Sep. 2011

Int Poster J Dent Oral Med 2011, Vol 13 No 3, Poster 547

Cross-contamination risks in the dental laboratory during denture processing

Language: English
 

Authors:
Prof. Mihaela Pauna, PhD, PhD student Madalina Malita, PhD student Iuliana Babiuc,
University of Medicine and Pharmacy Carol Davila Bucharest, Faculty of Dentistry, Department of Removable Prosthodontics, Bucharest, Romania
Lucia Ciudin, Daniela Cristea, Maria Condei, Madalina Baltoiu, Vasilica Ungureanu, Anca Petrini, Andi Marian Palade,
National Institute of Research-Development for Microbiology and Immunology Cantacuzino, Bucharest, Romania

Date/Event/Venue:
22-25th April 2010
15th BASS Congress
Thessaloniki, Greece
 

Introduction

Cross-contamination may arise during different prosthetic stages, such as impression, casts, occlusal rims, articulators, dental prostheses and during repairs, relining or polishing of the dentures.
 

Objectives

The aim of this study was to investigate the potential for microbial contamination in the dental laboratory during dentures' processing.
 

Material and Methods

A total of 14 patients from the Department of Removable Prosthodontics of the Faculty of Dental Medicine in Bucharest participated in this study. They were of both sexes, ranging in age from 48 to 84 years, wearing 20 removable dentures. The subjects were divided into 2 groups: partially edentulous (n=8) and completely edentulous (n=6).
The samples were collected from the dentures at the Faculty of Dentistry, using a cotton pad. The cotton pad was placed in coded tubes and sent to INCDMI Cantacuzino. The samples were inseminated and incubated then the isolated aerobic species were biochemically identified using API galleries, rapid ID and/or Vitek ID cards and PCR targeting either species/specific genetic regions or gft genes coding for pathogenicity.
 

Results

50 bacterial strains have been isolated from 20 collected samples. All the microbial strains were aerobic species.
First group – partially edentulous patients – 11 samples from 8 subjects were analyzed, which led to the identification of 30 bacterial strains. Two subjects displayed signs of stomatitis and 7 were diagnosed with advanced periodontitis.
Group II – totally edentulous patients – 9 samples from 6 patients were collected. Four patients showed signs of denture-induced stomatitis, sometimes in connection with denture defects of construction.

  Pacient sex/age Sample No./Date Sample collection area Isolated aerobic species
1 B.G./M/73 years 2c/06.05.08 Upper partial denture 1. S. plurianimalium
2. Proteus mirabilis
3. Candida spp. (frotiu)
2 C.M./F/73 years 5c/06.05.08 Impression surface of upper partial denture 1. S. intermedius
2. Neisseria spp
3. E. coli
    6c/06.05.08 Impression surface of lower partial denture 1. S. gordonii
2. S. mitis/oralis
3. Enterobacter cloacae
3 P.E./F/55 years 5c/27.05.08 Lower partial denture 1. S. parasanguinis
4 S.C./F/57 years 10c/27.05.08 Lower denture – frontal base 1. S. anginosus
2. S. parasanguinis
3. Candida spp.
5 H.I./F/65 years 7c/17.06.08 Impression surface of lower partial denture 1. Rothia mucilaginosa
2. S. parasanguinis
3. Enterococcus cecorum
6 M.R./F/80 years 8c/17.06.08 Impression surface – upper denture 1. S. mitis/oralis
2. S. plurianimalium
    10c/17.06.08 Impression surface – lower denture 1. S. plurianimalium
2. Klebsiella pneumoniae
7 S.B./F/48 years 8c/24.06.08 Impression surface 1. S. mitis/oralis
2. S. gordonii
8 B.E./F/70 years 10c/24.06.08 Impression surface – upper denture 1. S. gordonii
2. S. parasanguinis
3. Citrobacter braakii
4. Klebsiella oxytoca
    12c/24.06.08 Impression surface – lower denture 1. S. gordonii
2. S. mitis/oralis
3. Citrobacter braakii
4. Klebsiella oxytoca
Tab. 1: Group I
  Pacient sex/age Sample No./Date Sample collection area Isolated aerobic species
1 I.M./F/74 years 10c/06.05.08 Complete upper denture – calculus 1. E. coli
2 P.E./F/84 years 2c/20.05.08 Complete upper denture 1. S. mitis/oralis
2. S. parasanguinis
3. Sphingomonas paucimobilis
    4c/20.05.08 Complete lower denture 1. S. mitis/oralis
2. Rothia mucilaginosa
3 M.A./F/75 years 5c/10.06.08 Complete lower denture – frontal base (relined with resilient material) 1. S. mitis/oralis
2. S. parasanguinis
3. E. coli
4. Candida spp.
    7c/10.06.08 Impression surface – complete upper denture (relined with resilient material) 1.S. parasanguinis
2. Candida spp.
4 R.C./F/53 years 8c/10.06.08 Impression surface – complete upper denture 1. S. gordonii
2. S. mitis/oralis
5 G.S./F/80 years 12c/10.06.08 Complete lower denture 1. Gemella morbillorum
2. S. mitis/oralis
    14c/10.06.08 Impression surface – complete upper denture 1. Gemella morbillorum
2. S. alactolitycus
6 H.I./F/65 years 4c/17.06.08 Impression surface – complete upper denture (relined with resilient material) 1. Aerococcus viridians
2. Candida spp.
Tab. 2: Group II
Fig. 1: Puss in the proximity of a root (23). Microbial samples turned positive for E. coli. Fig. 2: A silicone impression was taken in order to add a dental clasp. The denture and the silicone material were immersed in Printosept for 10 minutes.
Fig. 3: Microbial analysis of the sample collected from the mucosal surface of this 8 years old denture turned positive for Enterobacter cloacae Fig. 4: Complete upper denture with heavy deposits of calculus. The microbial analysis isolated one strain of E. Coli and one strain of Pseudomonas aeruginosa, very sensible to multiple antibiotics.
 
Fig. 5: Complete upper denture with heavy deposits of calculus. The microbial analysis isolated one strain of E. Coli and one strain of Pseudomonas aeruginosa, very sensible to multiple antibiotics.
 
 

Conclusions

The isolated species from the dentures' surface were aerobic bacterias and fungi. They were generally part of the normal oral flora and could cause different pathologies especially in immunocompromised patients.
Enteric rods were present, in small number, signaling poor oral and denture hygiene. The isolated Pseudomonas spp. may play a role in the etiology of the periodontal disease.
3 out of 4 samples collected from dentures relined with resilient material turned positive for Candida spp. They are frequently associated with denture-induced stomatitis.
No anaerobic species was found on the surface of the dentures. However, studies analyzing the colonization of the internal porous system of the acrylic resin indicate the presence of anaerobic species at this level.
In conclusion, dentures tend to accumulate plaque and they become a reservoir for numerous microbial species, some of which may be responsible for a wide range of infections. A faulty manipulation in the dental office and in the laboratory of the removable dentures presents a risk of cross-contamination.
 

Literature

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This Poster was submitted by Prof. Mihaela Pauna.
 

Correspondence address:
Prof. Mihaela Pauna, PhD
University of Medicine Carol Davila Bucharest
Faculty of Dentistry, Department of Removable Prosthodontics
37 Dionisie Lupu Street
020021 Bucharest
Romania